Co2 is required as the carbon element is required for plant growth. All Plants need carbon or co2 in some form, like it or not, they need co2 to breath.. however with careful selection of plants, you may skip it as low tech plants requires less co2 than high/mid tech plants.
So what are the difference?
With Co2 injection ( proper Co2 setup):-
Pro and Cons
- Expensive but cheap in long run
- the setup occupies a lot of space and a bit ugly if its not camouflaged..lol
- can use with diffuser as its pressurized
- your plants will grow fast,
- your plants may start to pearl if the condition is right. ( http://theplantedtankblog.blogspot.sg/2013/07/pearling-effect-for-planted-tanks.html )
- to maximise plant growth, you may add more fertiliser/light and
- you may need to trim your plants more often
- you may experience some algae growth due to imbalance of nutrient..it a demand and supply issue
- if you stop co2 suddenly, you may experience sudden algae bloom as plants will be stunt and algae will take over
- can use with solenoid and turn it ON and OFF... less hassle and saves co2
Using DIY Co2:- mostly will be using yeast + sugar water to get the Co2
Pro and Cons
- Cheap but not efficient
- Not exactly eye candy to look at if you display it
- can't be used with certain co2 diffusser due to low pressure
- You may have some fast co2 production initially and almost zero production around 2 weeks down the road, so you need to change the mixture every 2 weeks ( i tested it, not doing it anymore)
- Unstable Co2 production, may lead to Black Brush Algae.. ugly
- The mixture smells like alcohol...well, that is the by product anyway, so Muslim friends might not like it.
- not for lazy people aka yours truly
Using Seachem Excel as carbon substitute
Pros and Cons
- Expensive in long run
- Half life is around 12hours, so it will be breakdown after 24 hours of exposing to light
- its algaecide:- stops/kills algae... but may kill your fauna/flora if overdosed/unproper usage ( WARNING)
- easy to dose
- no hassle, won't occupy a lot of space.
- good for low tech tanks, not for high tech plants unless you use it to control algae growth
- good for lazy + poor people...aka people like yours truly